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16-Channel organic electrochemical transistor arrays (OECTs) are developed for mapping the propagation and studying the characteristics of action potentials of primary cardiomyocytes. The physiological activities of a rat cardiomyocyte monolayer during a long-term culturing is revealed by this biocompatible, low-cost, and high transconductance organic electronic device. OECT has great potential to be used in cardiac and neuronal drug screening.

Microgrooved thin PLGA film (≈30 μm) is successfully fabricated on a Teflon mold, which could be readily peeled off and is used for the construction of a biomimetic cardiac patch. The contraction of it is studied with optical mapping on transmembrane action potential. Our results suggest that steady-state contraction could be easily established on it under regular electrical stimuli. Besides, the biomimetic cardiac patch recapitulates the anisotropic electrophysiological feature of native cardiac tissue and is much more refractory to premature stimuli than the random one constructed with non-grooved PLGA film, as proved by the reduced incidence of arrhythmia. Considering the good biocompatibility of PLGA as demonstrated in our study and the biodegradability of it, our biomimetic cardiac patch may find applications in the treatment of myocardial infarction. Moreover, the Teflon mold could be applied in the fabrication of various scaffolds with fine features for other tissues.

Ion channels are important cellular transmembrane proteins for passively transporting inorganic ions into or out of cells. The study of ion channels, or more broadly the cell electrophysiology, is not only beneficial to fundamental study, but also for drug discovery. One gold standard tool to study ion channel’s activities is patch clamp, which could provide the detection limit to single ion channel level. However, due to the delicate configuration used and membrane damage caused by high seal resistance requisite, it’s technically hard for patch clamp to monitor cells’ electrophysiological activities in multiple sites and for a long term. Microelectrode array and field-effect transistor array thus have been introduced for solving those issues by implementing an extracellular detection scheme. Nevertheless, they suffer the problem of low sensitivities while the rigid substrates used in those techniques make them hardly be applied to in vivo usages. In this thesis work, we intended to tackle these problems by developing a novel cell electrophysiological signal monitoring approach based on the organic electrochemical transistor (OECT) array, in which both high sensitivities and device mechanical flexibilities were achieved. A simple fabrication method, which is compatible to be used in standard fabrication facilities, was firstly developed for fabricating miniaturized OECT arrays on both rigid glass and flexible PET substrates. Their sensing abilities were then exemplified by monitoring the electrophysiological signals of transepithelial ion transport from human airway epithelial cells and action potentials from both HL-1 cells and primary rat cardiomyocytes. Meanwhile, drug screening capabilities of OECT based devices were also successfully demonstrated by accurately recording cell signal changes with corresponding drugs’ effects. With the high sensitivities and mechanical flexibilities, OECT arrays are promising to be integrated into novel biomedical devices for both

An organic electrochemical transistor array is integrated with human airway epithelial cells. This integration provides a novel method to couple transepithelial ion transport with electrical current. Activation and inhibition of transepithelial ion transport are readily detected with excellent time resolution. The organic electrochemical transistor array serves as a promising platform for physiological studies and drug testing. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

We report a simple staining-free gel electrophoresis method to simultaneously probe protease and nuclease. Utilizing gold nanoparticles (Au-NPs) dual-functionalized with DNA and peptide, the presence and concentration of nuclease and protease are determined concurrently from the relative position and intensity of the bands in the staining-free gel electrophoresis. The use of Au-NPs eliminates the need for staining processes and enables naked eye detection, while a mononucleotide-mediated approach facilitates the synthesis of DNA/peptide conjugated Au-NPs and simplifies the operation procedures. Multiplex detection and quantification of DNase I and trypsin are successfully demonstrated.